In the early days of McLaren’s MP4-12C development, it was suggested that the new mid-engine supercar would use AMG’s 6.2 liter V8. As things got awkward between Mercedes and McLaren though, a mysterious “German-built V10” was rumored to be have replaced the AMG unit under at least one testing prototype. In the end, McLaren built its own engine, the M838T. It’s a twin-turbocharged, direct-injected, 3.8 litre, 90° V8, developing about 600 horsepower at 8,500 RPM. 80 percent of its 442 lb-ft of torque is reportedly available under 2,000 RPM. Also, it looks like mechanical sex.

So, we’re looking at 155 to 160 hp/l, and 111 ft-lbs/l. Those are jaw-dropping numbers, even for forced induction. The GT-R, already off the deep end in technology, gets 125-130 hp/l and 110-115 ft-lbs/l. Different number of cylinders, different revs- roughly the same displacement. I am not an expert in the numerous methods for calculating and reporting horsepower, but are we actually seeing a 20-25% improvement in hp/l over what was already an amazing technological accomplishment? I know Nissan was reported as under-reporting the hp of the GT-R by some sources, but even so- this McLaren engine appears to be near-miraculous. I didn’t know street legal cars were in this kind of territory. Am I looking at the numbers wrong?

Nissan doesn’t really under-report the GT-R. All dynos I’ve seen suggest a car making 475-485 hp. 500 tops. Nothing like the “550” that some of the buff books and forum wags were hysterically claiming at one time.

I’m familiar with the Dynapack and Dastek used in the Japanese and UK (that one was funny… they took one reading below the power peak, one above it… and extrapolated a curve to obtain the power peak… pure bullsh*t) dyno-tests… and US commenters should be familiar with the Mustang used in the Edmund’s twin-test opposite the 911 Turbo… you’ll note that the “whp” numbers are all over the place.

See… not many people understand the variances and discrepancies in dynamometers and dyno-tests. But I have a pretty good idea of how badly some of the systems over- or under-quote, and I haven’t seen a number suggesting over 500 hp yet.

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The thing is… Nissan built a 3.8 liter twin-turbo mill that could likely do 550-600 hp uncorked. They electronically limit peak power to under 500 but keep the swelling torque-curve… which is what gives it that amazing performance.

Of course, I’d rather have the McLaren V8… just hope it sounds as epic as it looks… most turbocharged cars (GT-R included) sound like industrial vacuum cleaners.

I appreciate the response. I knew that there was some variability in the way these things were measured- but I didn’t know where the GT-R debate had ended up. I also enjoyed Paul’s declaration- “With forced induction, anything is possible.” In any case, that is one amazing engine- and yes, it looks like a hot chick… a very hot chick.

Its a late reply.. but I finally test drived the MP4-12C yesterday! Its the fastest factory road car I ever tested . The car handles brilliant, carbon fiber monocell results a road car with a go-cart like handling.. I would say, the cornering limit of the car is very high. I switch everything into “track mode”, I didn’t feel the car bumpy at all, this is a result of a piece of engineering art work, lightweight and high power super car.

Engine with turbos weights around 150kg . But the car has big turbo lag comparing with GTR, but top ends it will beat the GTR for sure due to V8 fitted with high flow turbos.

One thing have to say good about the gearbox . The gear shift is seamless and smooth. This is the best gearbox I ever driven comparing with all other double-clutched gearboxes (like PDK, DSG) . Even with stand still start, the electronic clutch is very smooth. This shows Mclarens effort in their software engineering for clutch control during launch.

Braking power….. absolutely amazing . With the car’s weight, it just brakes like a cart with carbon ceramic brakes and 6 piston calipers .